The goals of this research are the preparation and characterization of series of molybdenum (VI) complexes which have thiolate and phenolate ligands coordinated to the molybdenum ion trans to oxo groups, hence mutually cis. It is hypothesized that cis thiolate ligands can transfer electrons to a metal ion while forming a disulfide or a partial sulfur-sulfur bond. This may cause the labilization of oxo groups on Mo(VI) giving rise to reactions catalyzed by molybdoenzymes. Since the analogous reaction of phenolate ligands is much less likely, we can evaluate the probability of such reactions occuring in enzymes. The synthesis of a series of rigid ligands is proposed as well as studies of reactions of molybdenum complexes derived from those ligands. Spectroscopic studies and their potential applications to enzyme active analysis are also outlined.